Tuning Language Models by Proxy

Fuente: arXiv
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Hauptverfasser: Liu, Alisa, Han, Xiaochuang, Wang, Yizhong, Tsvetkov, Yulia, Choi, Yejin, Smith, Noah A.
Format: Preprint
Veröffentlicht: 2024
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author Liu, Alisa
Han, Xiaochuang
Wang, Yizhong
Tsvetkov, Yulia
Choi, Yejin
Smith, Noah A.
author_facet Liu, Alisa
Han, Xiaochuang
Wang, Yizhong
Tsvetkov, Yulia
Choi, Yejin
Smith, Noah A.
contents Despite the general capabilities of large pretrained language models, they consistently benefit from further adaptation to better achieve desired behaviors. However, tuning these models has become increasingly resource-intensive, or impossible when model weights are private. We introduce proxy-tuning, a lightweight decoding-time algorithm that operates on top of black-box LMs to achieve the same end as direct tuning, but by accessing only its predictions over the output vocabulary, not its parameters. Our method tunes a smaller LM, then applies the difference between the predictions of the small tuned and untuned LMs to shift the original predictions of the larger untuned model in the direction of tuning, while retaining the benefits of larger-scale pretraining. In experiments, when we apply proxy-tuning to Llama2-70B using proxies of only 7B size, we can close 88% of the gap between Llama2-70B and its truly-tuned chat version, when evaluated across knowledge, reasoning, and safety benchmarks. We then demonstrate the generality of proxy-tuning by applying it to domain adaptation on code, and task-specific finetuning on question-answering and math problems. Finally, we show how to proxy-tune a truly black-box LM, GPT-3.5, for temporal adaptation, increasing its knowledge about recent events. Our work demonstrates the promise of using small tuned LMs to efficiently customize large, potentially proprietary LMs through decoding-time guidance.
format Preprint
id arxiv_https___arxiv_org_abs_2401_08565
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Tuning Language Models by Proxy
Liu, Alisa
Han, Xiaochuang
Wang, Yizhong
Tsvetkov, Yulia
Choi, Yejin
Smith, Noah A.
Computation and Language
Despite the general capabilities of large pretrained language models, they consistently benefit from further adaptation to better achieve desired behaviors. However, tuning these models has become increasingly resource-intensive, or impossible when model weights are private. We introduce proxy-tuning, a lightweight decoding-time algorithm that operates on top of black-box LMs to achieve the same end as direct tuning, but by accessing only its predictions over the output vocabulary, not its parameters. Our method tunes a smaller LM, then applies the difference between the predictions of the small tuned and untuned LMs to shift the original predictions of the larger untuned model in the direction of tuning, while retaining the benefits of larger-scale pretraining. In experiments, when we apply proxy-tuning to Llama2-70B using proxies of only 7B size, we can close 88% of the gap between Llama2-70B and its truly-tuned chat version, when evaluated across knowledge, reasoning, and safety benchmarks. We then demonstrate the generality of proxy-tuning by applying it to domain adaptation on code, and task-specific finetuning on question-answering and math problems. Finally, we show how to proxy-tune a truly black-box LM, GPT-3.5, for temporal adaptation, increasing its knowledge about recent events. Our work demonstrates the promise of using small tuned LMs to efficiently customize large, potentially proprietary LMs through decoding-time guidance.
title Tuning Language Models by Proxy
topic Computation and Language
url https://arxiv.org/abs/2401.08565